5,025 research outputs found

    MULTISPECIES REVENUE FUNCTION ESTIMATION FOR NORTH PACIFIC GROUNDFISH FISHERIES

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    Multiproduct, multispecies revenue functions are estimated for the midwater and bottom-trawl pollock fisheries off Alaska. There are strong year and seasonal effects on coefficient estimates, and the technology is joint in outputs for each major operation type. The model is a step toward prediction of fishery regulatory effects.Resource /Energy Economics and Policy,

    Frequency of fab subtypes in acute myeloid leukemia patients at Aga Khan University Hospital Karachi

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    BACKGROUND: Acute myeloid leukemia (AML) is a heterogeneous disease. Therefore, various parameters are needed to classify this disease into subtypes, so that specific treatment approaches can be utilized effectively. The commonly used method for diagnosis and classification is based on FAB criteria using morphology and cytochemical stains. For some of the categories, immunophenotyping is necessary. The aim of present study is to determine the frequency of various sub types in acute myeloid leukemia using FAB criteria in our population. This will aid in the correct diagnosis of acute leukemia and hence proper management of the patients. MATERIALS AND METHODS: This is descriptive case control study conducted at Aga Khan University Hospital from January 1999 to December 2000. The total number of subjects was 116 that included both adults and children. The patients were diagnosed on the basis of bone marrow morphology using FAB classification. Cytochemistry was done in all cases, while immunophenotyping was considered only in those cases that were found to be problematic. RESULTS: Among 116 patients, 70 were males and 46 were females with male to female ratio 1.5:1. The age ranged between 6 months to 85 years with a mean age of 32 years. AML-M4 was the predominant French-American-British (FAB) subtype (36.2%) followed by M2 (30.25%), M3 (10.4%), M1 (8.7%), M0 (7.7%), M5a (3.5%), M5b (2.5%) and M6 (0.8%). CONCLUSIONS: The most common FAB subtype observed in our study was Acute myelomonocytic leukemia (M4) which is in accordance with studies reported from Saudia Arabia and a previous study reported from our institution. However,other national and international studies have reported Myeloblastic Leukemia with maturation (M2) as the predominant subtype of AML

    Tremorgenesis: a new conceptual scheme using reciprocally innervated circuit of neurons

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    Neural circuits controlling fast movements are inherently unsteady as a result of their reciprocal innervation. This instability is enhanced by increased membrane excitability. Recent studies indicate that the loss of external inhibition is an important factor in the pathogenesis of several tremor disorders such as essential tremor, cerebellar kinetic tremor or parkinsonian tremor. Shaikh and colleagues propose a new conceptual scheme to analyze tremor disorders. Oscillations are simulated by changing the intrinsic membrane properties of burst neurons. The authors use a model neuron of Hodgkin-Huxley type with added hyperpolarization activated cation current (Ih), low threshold calcium current (It), and GABA/glycine mediated chloride currents. Post-inhibitory rebound is taken into account. The model includes a reciprocally innervated circuit of neurons projecting to pairs of agonist and antagonist muscles. A set of four burst neurons has been simulated: inhibitory agonist, inhibitory antagonist, excitatory agonist, and excitatory antagonist. The model fits well with the known anatomical organization of neural circuits for limb movements in premotor/motor areas, and, interestingly, this model does not require any structural modification in the anatomical organization or connectivity of the constituent neurons. The authors simulate essential tremor when Ih is increased. Membrane excitability is augmented by up-regulating Ih and It. A high level of congruence with the recordings made in patients exhibiting essential tremor is reached. These simulations support the hypothesis that increased membrane excitability in potentially unsteady circuits generate oscillations mimicking tremor disorders encountered in daily practice. This new approach opens new perspectives for both the understanding and the treatment of neurological tremor. It provides the rationale for decreasing membrane excitability by acting on a normal ion channel in a context of impaired external inhibition

    FORMULATION OPTIMIZATION AND EVALUATION OF GASTRORETENTIVE TABLETS OF ONDANSETRON HCL

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    The aim of the work is to design Gastroretentive tablets of Ondansetron HCl for gastric retention by using 32 factorial designs. Floating tablets of Ondansetron HCl were prepared by direct compression method using polymers, sodium alginate and excipient. Gastroretentive tablets of Ondansetron HCl were successfully prepared by effervescent technique using different gel forming polymers- HPMC K200M, and sodium alginate. Formulation was optimized by design expert software. Floating tablets were evaluated for floating time, floating lag time, drug content, raft measurement and in vitro dissolution profile. The lag time is between 17-22 sec and floating time of the formulations for 12 hrs. The best fit model is Korsemeyer Peppas Model. From the study it is proof that the sustain release by floating tablets of Ondansetron HCl can be develop. Optimized batch selected was A3, The prepared gastroretentive test formulation was found to exhibit satisfactory physico-chemical characteristics at the end of 3 months, during the stability studies. The optimized formulation A3 was found to be stable at 400C/ 75% RH. Keywords: Gastric retention time, Ondansetron HCl, HPMC, sodium alginate, measurement of raft, Factorial design, stability studies.Â

    Effects of Climate Change on Mountain Waters: A Case Study of European Alps

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    The Alps play a vital role in the water supply of the region through the rivers Danube, Rhine, Po and Rhone while they are crucial to the ecosystem. Over the past two centuries, we witnessed the temperature to increase by +2 degrees, which is approximately three times higher than the global average. Under this study, the Alps are analyzed using regional climatic models for possible projections in order to understand the climatic changes impact on the water cycle, particularly on runoff. The scenario is based on assumptions of future greenhouse gases emissions. The regional model results show the consistent warming trend in the last 30-year span: temperature in winter may increase by 3 to 4.5°C and summers by 4 to 5.5°C. The precipitation regime may also be altered: increasing about 10-50% in winter and decreasing about 30-60% in summer. The changes in the amount of precipitation are not uninformed. Differences are observed particularly between the North West and South East part of the Alps. Due to the projected changes in alpine rainfall and temperature patterns, the seasonality of alpine flow regime will also be altered: massive rise will occur in winter and a significant reduction in summer. The typical low flow period during winter will also be shifted to late summer and autumn
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